With three bomb attacks in Londonderry as well as Bangor and Kilkeel, Co Down, in less than a week, the escalating campaign is causing increasing concern among security chiefs in Belfast and Dublin.

Political representatives of the dissident groups have already rejected an invitation to talks by Sinn Fein president Gerry Adams, but Mr Paterson made clear there will be no moves by the Government to start a negotiating process in a bid to persuade the dissidents to end the attacks.

A major security operation is due to be held in Derry next Saturday when thousands of bandsmen and members of the loyalist Apprentice Boys take part in their annual parade.

The two main dissident factions are the Continuity IRA and the Real IRA, the organisation with bombed Omagh in August 1998, killing 29 people.

Mr Paterson insisted today that they would not be allowed to disrupt the political process.

He told BBC Radio Ulster: "You cannot have any meaningful talks with people who are not committed to peaceful means. They are not listening. They are disparate. They are a very small armed group with no discipline or clear focus on where they are going."